Nuclear Medicine

What is nuclear medicine?

Nuclear medicine uses radiation to provide information about a person’s anatomy and the functioning of specific organs. This information enables physicians to provide a quick, accurate diagnosis of conditions such as cancer, heart disease, thyroid disorders and bone fractures. In some cases, radiation is used to treat this condition.

Is nuclear medicine safe?

Nuclear medicine is extremely safe because the radioactive tracers or radiopharmaceuticals commonly used are quickly eliminated from the body through its natural functions. In addition, the tracers used rapidly lose their radioactivity. In most cases, the dose of radiation necessary for a scan is very small. For example, a patient having a lung scan is exposed to the same dose of radiation they would receive from two return air flights between Sydney and London.

How are radiopharmaceuticals produced?

Australia is one of the very few nations in the world to produce the radioactive tracers necessary for diagnostic nuclear medicine. Without the ability to produce radiopharmaceuticals here, we would have to import them from as far away as Europe and Canada.

They are manufactured at two facilities operated by ANSTO – a nuclear research reactor located at Lucas Heights, near Sydney, and at its cyclotron at Camperdown in Sydney. The manufacturing process at both facilities is regulated by strict quality control requirements as approved by Government. The reactor and the cyclotron each produces different types of radiopharmaceuticals that are supplied to nuclear medicine centres across Australia. Hence the reactor and the cyclotron are necessary.

Every year thousands of people are diagnosed and treated at nuclear medicine centres. Without access to this vital technology, these people would be facing a reduced quality of medical care.

When is a scan needed?

There is about a one in two chance of an Australian needing a nuclear medicine scan during his or her lifetime. Scans using radiopharmaceuticals can diagnose all sorts of conditions. Scans of the heart, thyroid, lungs and kidney are common. However. by far the majority of scans involve the skeleton. These are usually carried out to diagnose infection, tumour spread and fractures or sports injuries.

Should I prepare for a scan in any way?

Some tests may require special preparation. As with other tests, if you are pregnant or think you may be pregnant or if you are breastfeeding you must tell your physician. It is important that you read all the material given to you prior to your appointment.

What can I expect when I have a Scan?

When you undergo a scan, a radiopharmaceutical will be given, either by injection into a vein, by mouth or through a breathing device. The radiopharmaceutical will concentrate in the particular part of your body under investigation.

Sometimes you may have to wait for a few hours or even a day or two after the radiopharmaceutical has been administered for the scan to be done. This is because it may take a while for the radiopharmaceutical to lodge in the part of your body to be examined. As the radiopharmaceutical travels, it continuously gives off invisible radiation, known as gamma rays.

Using a special camera called a gamma camera, doctors can detect the location of the radiopharmaceutical in your body. During your scan, the camera will be positioned close to the part of your body being scanned. Computers enhance the images taken by the camera on a screen and the images will be preserved on film for further study by doctors who will be able to tell if the part of your body being tested is functioning normally.

Will it hurt?

No. A scan involves nothing more painful than an injection into a vein.

Are there different types of scans?

Yes, there is a gamma camera imaging and PET imaging. Gamma imaging operates in two different modes. If your doctor refers you for a nuclear medicine scan, one of the following methods will be used.

PLANAR lmaging

This is the most common of the three methods. It involves the injection into the body of a small amount of a chemical substance tagged with a radioactive tracer. Depending on the chemical substance used, the radiopharmaceutical concentrates in the part of the body being investigated, for example the skeleton, lungs, heart or liver and gives off gamma rays. A gamma camera produces a two-dimensional image of the radioactivity occurring in that organ.

SPECT lmaging

SPECT or single photon emission computed tomography is also widely used and the process of injecting a radioactive tracer is the same as for the PLANAR technique. The gamma camera moves around the body providing a series of images and this takes about 30 minutes. SPECT and PLANAR imaging are highly convenient technologies as they use radiopharmaceuticals, which can be easily distributed, stored and mixed ready for use at nuclear medicine clinics and hospitals across Australia.

PET lmaging

Positron emission tomography (PET) is a very similar technique to SPECT but provides more detailed images. However, the radiopharmaceuticals required for PET have very short half-lives and are produced by the cyclotron.

Will I have to stay in hospital?

Patients having a diagnostic scan will often be asked to stay in the nuclear medicine department for a few hours, although in some cases patients are asked to return for a number of visits or to stay in hospital for a short period.

If you are undergoing therapy, particularly for an overactive thyroid gland, you will probably be treated as an outpatient and will not need to stay in hospital. If you do stay, then you will usually only be in hospital for two or three days. This is not because of any risk to your health but because doctors want to ensure that radioactive materials are dealt with safely when they are excreted from your body.

What does nuclear medicine treatment involve?

By far the widest application of nuclear medicine is for diagnosis. However, there are a number of occasions when radioactive materials are used to treat certain conditions, particularly cancer. This is known as therapy.

Nuclear Medicine therapy usually involves drinking radiopharmaceuticals and the most common conditions treated in this way are overactive thyroid or thyroid cancer. Radiopharmaceuticals are also injected into the body, usually the joints, to treat such conditions such as arthritis. Newer treatments involve the intravenous injection of radioparmaceuticals for the relief of pain from tumours that have spread to bone.

In Australia many patients are treated with radiopharmaceuticals that have a medical effect on their bodies. For most, one dose is all that is required.

Are there any side effects?

Side effects are extremely rare for diagnostic scans. When radiation or radiopharmaceuticals are used in therapy, there are sometimes minor side effects such as nausea or swelling in the salivary glands. To prevent the latter, patients are advised to simply suck lollies.

Who carries out nuclear medicine procedures?

If your doctor recommends you for a scan or nuclear medicine treatment, you will be placed in the care of a team of specially trained professionals. Physicians, technologists, and pharmacists will ensure that you receive a high level of care and that your doctor is provided with accurate reports on your condition.

What happens after a scan or therapy?

The specially trained physicians will report on the scan’s appearance and send the results to your doctor to evaluate, together with those of any other test you may have had. In the majority of cases, you will be able to continue your daily lifestyle as usual.

What are the benefits of nuclear medicine?

Nuclear medicine enables doctors to produce a quick and accurate diagnosis for a wide range of conditions and diseases at any age. In turn, this allows the appropriate treatment to begin as early as possible, which gives a far greater change of being fully effective. In addition, the tests are painless and most scans expose patients to only a minimum of radiation. It is the only way to examine whether some tissues are functioning properly. Therapy using nuclear medicine is an effective, safe and relatively inexpensive way of controlling and in some cases, eliminating certain conditions such as overactive thyroid, thyroid cancer and arthritis. Nuclear medicine is a vital part of healthcare as it gives many people the opportunity of continuing to live full and healthy lives.